Practice Exam 3 - Environmental Science - page 306

23. C Oils, trash, debris, and other flammable chemicals were floating on the surface of the Cuyahoga
River when it caught fire in 1969. This was not the first river fire, but it brought awareness to the issue
because Time magazine published an article about the event.
24. A CAFE is an acronym for corporate average fuel economy, which is a regulation that established the
average miles-per-gallon of a manufacturer's fleet of cars. It was also expanded to include light trucks.
25. C Formaldehyde is found almost entirely as an indoor air pollutant, coming from pressed woods, car-
pets, and furniture. Both carbon dioxide and carbon monoxide are found indoors, but they are also
found in large quantities outdoors. Nitrous oxide and sulfur dioxide are found mostly outdoors.
26. D One concern with GMOs is that the genes from these engineered plants and animals will uninten-
tionally spread to the naturally occurring plants and animals via dispersion and/or interbreeding.
27. B Ozone is destroyed by chlorofluorocarbons (CFCs) when CFCs react with UV radiation from the sun
to produce more CFCs while releasing a chlorine atom. (Note that the acronym CFC is shorthand and
not a proper representation of the chemical's atoms, so chemical equations containing "CFC" need not
appear balanced.) The chlorine atom then reacts with ozone to form chlorine monoxide and oxygen.
The ClO reacts with ozone to form more chlorine molecules and oxygen. This is an ongoing cycle be-
cause more chlorine atoms are created in the process.
28. C Phytoplankton are the producers in this food web, turning the sun's energy into energy that is usable
by the rest of the ocean food chain.
29. D Giant sequoias, California condors, and humans are K-selected species. They take a long time to
reach maturity and generally produce only a few offspring at a time.
30. C Coal is formed when vegetation dies and is covered in mud, creating an anaerobic environment.
Over millions of years pressure squeezes out the liquid, leaving the carbon matter behind to form com-
plex chains of carbon compounds. These carbon compounds make up coal.
31. D Global climate change will have an effect on the human food supply. Crops grown along coastal
areas may be flooded by rising seas and, thus, have to be relocated. Changes in precipitation patterns
may lead to a need for an increase in crop irrigation or the need to move fields to areas that receive
more rainfall. Higher temperatures also may lower crop yields or require a change in selecting where
certain crops are grown.
32. B An indicator species reflects the quality of the water, soil, or air in a given area. If pollutants are
present or the ecosystem is altered, these indicator species that are more sensitive to change will be af-
fected first, likely dying, becoming ill, or moving from one location to another.
33. E Overgrazing leads to a reduction in native biodiversity because many native grasses struggle to cul-
tivate and grow after being overgrazed. This could be due to reduced soil quality, soil compaction, or an
intrusion of invasive species.
34. B CFCs were not developed until the 1930s, when they were manufactured in large quantities for use
as refrigerants.
35. B Denitrification is the process by which bacteria convert nitrates (NO 3 - ) into gaseous nitrogen (N 2 ),
which is released into the atmosphere.
36. C Nitrification is the process of converting ammonium (NH 4 + ) into both nitrite ions (NO 2 - ) and ni-
trate ions (NO 3 - ), both of which can be used by plants.